The International Tribunal for the Law of the Sea (ITLOS), yesterday began hearing the case on the maritime boundary dispute between Ghana and Cote d’Ivoire.

Legal representatives of both countries made their oral arguments before a special five-member chamber, which comprises international judges including a Ghanaian, Justice Thomas Mensah.

The chamber is to decide a request for provisional measure sought by Cote D’Ivoire, on oil and gas exploitation ongoing off the shores of Ghana.

A decision in favour of Côte d’Ivoire will stop Ghana’s partner, Tullow Oil, from drilling oil in the disputed maritime areas as regards the 10 territories, which Cote d’Ivoire claims are part of its maritime boundary. By contrast, a denial of Côte d’Ivoire’s request would enable Tullow Oil to continue with its operations.

The Co-Agent of Cote d’Ivoire, Ibrahim Diaby, who first made a case, asked the tribunal to stop Ghana from continuing with its oil exploitation pending the final settlement of the dispute.

He argued that it was inappropriate for Ghana to delimit the maritime and create oil blocks for itself, using the equidistance line while the two countries had not reached agreement on the delimitations.

“However, the western limit of the disputed area is uncertain on account of Ghana’s inconsistent position, at least at this stage of the proceedings. That is to say: in so far as Côte d’Ivoire can tell, the line used by Ghana to delimit its oil and gas concessions, which it calls an equidistance line, departs from strict equidistance as established by Côte d’Ivoire on the basis of recent coastal surveys,” he said.

He further argued that “Although determining a provisional equidistance line is a matter of the merit, as Ghana stated in its notification of arbitration, this significant discrepancy between strict equidistance and the line advocated by Ghana already raises problems at this early stage of the proceedings because of the location of the oil blocks for which Ghana has granted concessions; these straddle the strict equidistance line”.

The Attorney-General and Minister of Justice, Mrs. Marietta Brew Appiah-Oppong, in her argument for the state, disagreed with the new formula used by Cote D’Ivoire to delimit the maritime.

She argued that the newly claimed maritime used by Cote d’Ivoire was based on a bisector approach and was a clear abandonment of a long-agreed boundary line that was based on equidistance.

“As the history demonstrates, Côte d’Ivoire’s new approach is the culmination of a series of radical and unprincipled departures from an equidistance approach which both parties had applied for decades, and reliance on which Ghana has granted concessions, entered into contracts, acquired rights, and undertaken extensive contractual obligations with international oil companies,” she said.

She said that “having allowed those steps to be taken, with full knowledge and acceptance, Côte d’Ivoire now sought to bring operations on the Ghana side of the long-recognised border to an abrupt halt. Nowhere in its request does Côte d’Ivoire acknowledge its own practice over decades or the immense and irreparable harm which the measures it seeks would cause to Ghana”.

The two-day round of oral arguments are as a result of a request for provisional measures filed by Côte d’Ivoire on February 27, 2015, in which it sought that Ghana suspends oil exploration and exploitation until the Tribunal decides which of the two countries owns the disputed maritime region.

In addition, Côte d’Ivoire is seeking an order to restrain Ghana from “granting any new permit for oil exploration and exploitation in the disputed area” and to preserve the “continental shelf, the waters superjacent to it, and its subsoil”.

Côte d’Ivoire filed its request for provisional measures pursuant to Article 290 (1) of the United Nations Convention on the Law of the Sea (UNCLOS), which provides that a party may request for the prescription of provisional measures pending the outcome of the dispute. Article 290 (5) of the UNCLOS authorises the Tribunal to grant such a request if it is satisfied that it would have prima facie jurisdiction and to “preserve the rights of the parties or protect the marine environment, pending the outcome of the dispute”.

Ghana initiated arbitration under Annex VII of the UNCLOS in September last year, seeking an affirmation of its rights in the disputed maritime boundary.

The tribunal comprises the two ad hoc judges, one each chosen by Ghana and Côte d’Ivoire, and three permanent judges of the Tribunal. A decision on the request for provisional measures is expected in April 2015.

The tribunal has granted requests for provisional measures in cases where it was satisfied that it would have prima facie jurisdiction over the dispute and when it believes that granting such a request is urgently needed to preserve the rights of the parties or protect the marine environment.

Both Ghana and Côte d’Ivoire are parties to the UNCLOS and the jurisdictional issue was resolved on December 3, 2014 by agreement between the two countries in consultations with the President of the Tribunal, acting pursuant to Annex VII of the UNCLOS.

The most challenging question for the tribunal, however, is to resolve whether denying Côte d’Ivoire’s request or granting it will preserve the rights of both parties.

Ghana has already granted a permit to Tullow Oil, which has been exploring and drilling oil in the disputed 10 territories. But Ghana insists that it would prevail in the substantive case, counting on the tribunal’s likely use of the equidistance method to delimit the maritime boundary. A decision on that is also not expected until December 2017.